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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#873841 | #9553. The Hermit | 1903331632 | WA | 8ms | 19212kb | C++23 | 1.6kb | 2025-01-27 00:59:39 | 2025-01-27 00:59:40 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e6 + 10;
#define pii pair<int, int>
#define lowbit(x) (x & (-x))
const int mod = 998244353;
int fact[N];
int infact[N];
int qmi(int a, int b)
{
a %= mod;
int res = 1;
while (b)
{
if (b & 1)
res = res * a % mod;
a = a * a % mod;
b >>= 1;
}
return res;
}
void init()
{
fact[0] = 1;
for (int i = 1; i < N; i++)
fact[i] = fact[i - 1] * i % mod;
infact[N - 1] = qmi(fact[N - 1], mod - 2);
for (int i = N - 2; i >= 1; i--)
infact[i] = infact[i + 1] * (i + 1) % mod;
}
int C(int n, int m)
{
if (m < 0 || m > n)
return 0;
return fact[n] * infact[n - m] % mod * infact[m] % mod;
}
void solve()
{
int n, m;
cin >> m >> n;
unordered_map<int, unordered_map<int, int>> f;
for (int i = 1; i <= m; i++)
{
f[1][i] = 1;
}
int res = n * C(m, n) % mod;
for (int i = 1; i <= n; i++)
{
for (auto &[x, y] : f[i])
{
res = res - f[i][x] * C(m / x - 1, n - i) % mod;
res %= mod;
if (res < 0)
res += mod;
// f[i][x] = y;
for (int j = 2; j * x <= m && i + 1 <= n; j++)
{
(f[i + 1][j * x] += f[i][x]) %= mod;
}
}
}
cout << res << '\n';
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int t = 1;
init();
// cin >> t;
while (t--)
solve();
}
Details
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Test #1:
score: 0
Wrong Answer
time: 8ms
memory: 19212kb
input:
4 3
output:
9
result:
wrong answer 1st numbers differ - expected: '7', found: '9'